錯誤致命異常：AsyncTask＃1 android

Question

我正在做一個用於android的程序，該程序檢查數據庫中是否存在名為sms的行。 如果是這樣，則獲取號碼，文本和ID並發送消息。

但是，有一個我無法理解的錯誤。 我正在使用以下代碼檢查數據庫：

public class AsyncTaskParseJson extends AsyncTask<String, String, String> {

    TextView tres = (TextView) findViewById(R.id.txtresult);
    final String TAG = "AsyncTaskParseJson.java";

    // set your json string url here
    String yourJsonStringUrl= "http://192.168.1.7/aplicacao_sms/load_sms.php";
    //String yourJsonStringUrl = "http://demo.codeofaninja.com/tutorials/json-example-with-php/index.php";
    // contacts JSONArray
    JSONArray dataJsonArr = null;

    @Override
    protected void onPreExecute() {}

    @Override
    protected String doInBackground(String... arg0) {


        try {



            // instantiate our json parser
            JsonParser jParser = new JsonParser();

            // get json string from url
            JSONObject json = jParser.getJSONFromUrl(yourJsonStringUrl);

            // get the array of users
            dataJsonArr = json.getJSONArray("products");

            // loop through all users

            for (int i = 0; i < dataJsonArr.length(); i++) {
                JSONObject c = dataJsonArr.getJSONObject(i);
                String id=c.getString("id");
                String numero=c.getString("numero");
                String msg=c.getString("msg");


                send_sms(numero, msg, id);

            }
            dataJsonArr = json.getJSONArray("products");
            JSONObject c = dataJsonArr.getJSONObject(0);

        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(String strFromDoInBg) {}
}

當執行時是錯誤的：

 08-17 14:13:39.993    7781-7794/pt.styledesign.outro_teste W/dalvikvm﹕ threadid=11: thread exiting with uncaught exception (group=0x40de22a0)
08-17 14:13:40.393    7781-7794/pt.styledesign.outro_teste E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
    java.lang.RuntimeException: An error occured while executing doInBackground()
            at android.os.AsyncTask$3.done(AsyncTask.java:299)
            at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
            at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
            at java.lang.Thread.run(Thread.java:856)
     Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
            at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:5083)
            at android.view.ViewRootImpl.requestLayout(ViewRootImpl.java:976)
            at android.view.View.requestLayout(View.java:15520)
            at android.view.View.requestLayout(View.java:15520)
            at android.view.View.requestLayout(View.java:15520)
            at android.view.View.requestLayout(View.java:15520)
            at android.widget.RelativeLayout.requestLayout(RelativeLayout.java:292)
            at android.view.View.requestLayout(View.java:15520)
            at android.widget.ScrollView.requestLayout(ScrollView.java:1711)
            at android.view.View.requestLayout(View.java:15520)
            at android.widget.TextView.checkForResize(TextView.java:6677)
            at android.widget.TextView.updateAfterEdit(TextView.java:7575)
            at android.widget.TextView.handleTextChanged(TextView.java:7585)
            at android.widget.TextView$ChangeWatcher.onTextChanged(TextView.java:9371)
            at android.text.SpannableStringBuilder.sendTextChanged(SpannableStringBuilder.java:964)
            at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:498)
            at android.text.SpannableStringBuilder.append(SpannableStringBuilder.java:253)
            at android.text.SpannableStringBuilder.append(SpannableStringBuilder.java:30)
            at android.widget.TextView.append(TextView.java:3367)
            at android.widget.TextView.append(TextView.java:3354)
            at pt.styledesign.outro_teste.MainActivity.send_sms(MainActivity.java:189)
            at pt.styledesign.outro_teste.MainActivity.access$000(MainActivity.java:23)
            at pt.styledesign.outro_teste.MainActivity$AsyncTaskParseJson.doInBackground(MainActivity.java:87)
            at pt.styledesign.outro_teste.MainActivity$AsyncTaskParseJson.doInBackground(MainActivity.java:47)
            at android.os.AsyncTask$2.call(AsyncTask.java:287)
            at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
            at java.util.concurrent.FutureTask.run(FutureTask.java:137)
            at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
            at java.lang.Thread.run(Thread.java:856)

誰能幫我？

Answer 1

您的問題是由以下原因引起的：

android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

您無法通過doInBackground（）方法訪問任何UI元素。 安全的方法是使用publishProgress()和onPostExecute() 。

因此，您可能需要將send_sms()的參數包裝到一個新對象中，並將其發布到publishProgress() ，然后可以在onProgressUpdate()方法上更新TextView tres 。

Answer 2

因為您正在使用doInBackground（）方法更新UI，所以可以得到此異常。

像這樣更改您的AsyncTask。

public class AsyncTaskParseJson extends AsyncTask<String, Void, JSONObject> {

    TextView tres = (TextView) findViewById(R.id.txtresult);
    final String TAG = "AsyncTaskParseJson.java";

    // set your json string url here
    String yourJsonStringUrl= "http://192.168.1.7/aplicacao_sms/load_sms.php";
    //String yourJsonStringUrl = "http://demo.codeofaninja.com/tutorials/json-example-with-php/index.php";
    // contacts JSONArray
    JSONArray dataJsonArr = null;

    @Override
    protected void onPreExecute() {}

    @Override
    protected JSONObject doInBackground(String... arg0) {

        try {
            // instantiate our json parser
            JsonParser jParser = new JsonParser();

            // get json string from url
            JSONObject json = jParser.getJSONFromUrl(yourJsonStringUrl);
            return json;
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(JSONObject json) {
          try {

            // get the array of users
            dataJsonArr = json.getJSONArray("products");

            // loop through all users

            for (int i = 0; i < dataJsonArr.length(); i++) {
                JSONObject c = dataJsonArr.getJSONObject(i);
                String id=c.getString("id");
                String numero=c.getString("numero");
                String msg=c.getString("msg");
                send_sms(numero, msg, id);

            }
            dataJsonArr = json.getJSONArray("products");
            JSONObject c = dataJsonArr.getJSONObject(0);

        } catch (JSONException e) {
            e.printStackTrace();
        }
  }
}

希望對您有所幫助！